Telephone system



Sept. 18, 1934.

/2f/ PJM-4135,

F. PFLEIDERER 1,974,193

TELEPHONE SYSTEM Filed May 25, 1932 ikmwa 2 Sheets-Sheet l MQMQ@ Sept. 1S, 1934. v F PFLE|DERKER 1,974,193

TELEPHONE SYSTEM I Filed May 25. 1932 2 SheetS-Sheei 2 Ue? Z3 ra r l W ffl Il; u )44 @31453 fm I ij?! hwg-EF P rfl Pfleiderer Patented Sept. 1.8,

om-TED STATES-f rails TELEPHONE. SYSTEM Fritz Piieiderer, Berlin-Wilmersdorf, Germany,

assigner to Siemens & Halske Aktiengesellschaft, Siemensstadt, near Berlin, Germany Application May 25, 1932, Serial No. 613,349

- Inl Germany June 4, 1931 8V Claims. (Cl. 179-27) The .present invention'relates to a circuit arrangement;K for impulsek transmission in communication systems, more particularly in tele-- phone systems.

- When setting up a toll connection-with the' assistance of an operator in't'elephone systems, it is necessary to transmit various switching'operations overv the junction-lines connecting the-` Y operators position with the required-subscribers 10 exchange, such switching-operations consisting of, for. example, seizure, setting and-release of connecting devices, setting" up av speaking route for the operator incase the required subscribers applying various potentials to onevv or both they speaking leads either' infa uniformor' varying sequence, which potentials -then initiate the in- 'dividual switching operations.

which alternating currentis used for the setting of the connecting-devices over the `junction lines the' problem is solved byv initiating the iii-- dividual switching operations either by impulses -varying in'length or impulses -of equal length but differing as to number.

The present invention-now provides a new and satisfactory solution' of the problem over and above arrangements of known-type by arranging 3'5an impulse receiving-relay at the incoming-end' of a junctionfline to inuence switching deviceswhich cause various switching operationsto-be carried out according to the number and length of the impulses receivedby said impulse receiv- `40ing relay. l

The accompanying drawings showan'embodiment of the invention. An arrangement'- for a toll connection-in telephone traffic is shown in which a voice' frequency alternating current is `iused-for transmitting impulses over along junction line.

The switching-operation taking place when a toll connection is setup will be described below to the extent in which-they are embodied inthe llfeature of the invention; Switching operations and circuits of no importance for the understanding ofthe invention have purposely been omitted.

Itiwill-be-,assumed that a call from a distant subscriber who requires av connection with-the 'subscriber 13nin exchange; A--is received at the- In systems l int toll position FP. The operator at the toll position FP who now completes the connection between'` the distant subscriber and the requiredsubscriber Tn iirst -depresses the key BT and thereby produces a short impulse which passes from-thetoll position FP over` the junction line VL through the transformers which terminatev said junction line, and through the impulse repeaters U62- and UeS to the final seleotor'LW-fl over which the required subscriber may be acc'essible.

The depression of the key BT causes relay Cl at the toll position FP to be energized. Relay Cl closes 'the following circuit for relay J l: earth, contacts lcl, 2`2ul, winding of relay J 1, battery, earth'. Relay J1 is energized and applies the alternating current source of supply WQ to the two speaking leads over its contact-lil and 571-. This sets up a short impulse to the signal receiver SE, tuned to a voice frequency, in the repeater Ue2in exchange A over the -junction line VL, terminating in the two` transformers. The duration of thisY impulse depends upon the energization of relay U1.V The followiirT circuit is closed for this relayv Ul when relay Cl -is energized: earth, contacts 101,*251, winding of relay Ul,v battery, earth. Relay U1 is energized with slow action. The circuit for relay'Jl is opened after relay Ul was energized and consequently opened its contact' 22u1.

The' short impulse imparted to the signal receiver SE causes relay A2 in the repeater Ue2 to be energized. Relay A2, over its contact 1a2, closes a circuit for relay J2.- n addition, relay T2 is energized over earth, contact 7a2, 5222,- Y lwinding of relay T2, resistance W77, battery,

earth. Relay T2 is placed in a locking circuit over its ownV contact 4t2. The following circuit for relay C2 is closedY due to the energization of relay J2: earth, contact 137'2, winding of relay C2, contact-11102, battery, earth. The slow acting relay-'V2 also is energized over contact 187`2-by relay-J2,- The energization of relays C2 and V2 prevents relay G2 from being energized since' these relays form a' short` circuit for relay G2 4by the closing of their contacts 8c2 and 10112. Relay C3 in the repeater U63- is energized over contact 38c2 due to the energization of relay C2.

Relay C3 in turn closes the circuit to the final selector Lwliby means of contact 1203 in which relay C4 is energized. Relay Ce prepares the circuit to the subscriber Tn which extends over the test-relay PelV and the c-wiper of the final-selector LW4-by'- closing its contact les.

Relays A2,l J2 and V2 in the repeater Ue2 'release at the end of this impulse. Relay G2 is now energized in the following circuit due to the release of relay V2: earth, contact 8c2, winding of relay G2, battery, earth. Relay T2 remains energized over its contact 4t2 as mentioned above. Contacts 2992 and 3Gg2 are closed when relay G2 is energized and the closing of these contacts prepares the circuit for the transmission of the selecting impulses.

It should be mentioned in this connection that when the impulse reaches the repeater Ue2 and relays .l2 and T2 are energized over contacts 2272 and 21t2 a circuit is closed for the rotary magnet Dm of a discriminator so that said discriminator moves one step. This has no consequence in the present case due to the fact that relay T2 remains energized. After the release of relays J2 and V2, however, a circuit is closed over earth, interrupter RU, wiper dml of the discriminator contacts 19112, 2fi2, rotary magnet Dm, battery, earth, in which the discriminator is restored to normal.

The operato-r at the toll position FP now commences to dial for the purpose of setting the final selector LW4 to the required subscribers line. The impulse contacts n.97' are closed at each impulse which causes relay Jl to be intermittently energized and ie-energized in the following circuit: earth, impulse contact 11,57', contacts Scl, winding of relay 5l, battery, earth. The impulses are transmitted over the junction line VL to the signal receiver SE and thence to relay A2 by means of contact Llil and 571 which re-connect the alternating current source of supply WQ to the speaking leads. Relay A2 is energized and re-energizes relays J2 and V2. The impulses are transmitted from the repeater Ue2 to the repeater Ueli by applying earth to the a-lead and control potential to the b-lead. The appropriate circuits being of no importance for the invention have not been shown. 1n a similar manner the irnpulses are transmitted from the repeater Ue3 to the final selector LW4 by applying earth to the a-lead and control potential to the b-lead. Even these circuits have no bearing on the nature of the invention and therefore have been omitted. When the final selector LVS/'4 has been duly set to the subscriber Tn by the impulse series which the toll operator transmitted, the test relay P4 is energized if the line is idle. The test relay guards the line in known manner by means of its contact 15124 and switches through the two speaking leads with the aid of its contacts 5ptl and 6104. It also applies a potential to the b-lead over contact 9394 and consequently closes the following circuit for relay W3 in the repeater UeS: earth, battery, resistance W78, contact 97A, b-lead, contacts 71'3, 8e3, winding I of relay W3, earth. Relay WB is energized and placed in the following locking circuit: earth, contacts 1303, 14103, winding I1 of relay W3, battery, earth.

The operator at the toll position FP who receives no busy signal if the subscribers line is idle now depresses the ringing key RT an extended period. This connects the ringing current source of supply in the repeater Ue3 to the line leading to the required subscriber Tn. The pressing down of the ringing key RT namely, causes relay J l to be re-energized over earth, key RT, Contact 3cl, winding of relay J1, battery, earth. Relay J l, in the manner described above, sends a long impulse by means of its contacts 451 and 571 to the voice frequency receiver SE in the repeater U62. Relay A2 which is then energized in turn re-energizes relay J2 and relay J2 causes the slow acting relay V2 to be energized. Relay V2 closes its contact 6122 and due' to the longer impulse which causes relay T2 to be short circuited an extended period over earth, contacts 7a2, 6122, it releases with slow action. The following circuit for the rotary magnet Dm of the discriminator was closed on the energize.- tion of relay J2: earth, contacts 227'2, 21t2, winding of the rotary magnet Dm, battery, earth. The rotary magnet Dm advances the switch wipers of the discriminatcr one step. The switch wiper (1l/m2 then reaches position l over which the following circuit for relay X2 is closed after relay T2 has released: earth, contacts 1402, 15t2, switch wiper dvr/L2, winding of relay X2, battery, earth. Relay X2 is energized and closes a circuit for relay B3 in the repeater Ue?, as follows: earth, battery, contacts 231r2, 31t2, 347:2, 3092, 3502, winding of relay B3, battery, earth. Relay B3 forms the following circuit for relay R3, earth, contacts 19b3, 18u13, winding of relay R3, battery, earth. Relay R3 is energized and, by closing its contacts lGS and llr, connects the ringing current source of supply RQ to the two speaking leads passing over the nal selector LW4= to the subscriber Tn. The subscriber Tn is now called by the ringing signal. The further circuits formed when the subscriber lifts his receiver have not been shown since they are of no interest in the present case. At the end of the impuse series the discriminator is restored to normal after the release of relays A2, J2 and V2 over: earth, interrupter RU, switch wiper dml, contacts 1902, 20y'2, winding of the rotary magnet Dm.

The case will new be considered when the called subscribed Tn is engaged in a local call at the time when the nal selector LW4 is set to his line. In such a case the operator at the toll position FP must have the facility of being able to communicate with the subscriber Tn in order to inform him of the incoming toll call and request him to replace his receiver. With the object of cutting in on the existing `lccal call the operator depresses the switch key AT1 and AT2 at the toll position FP. This causes first a short and then a long impulse to be transmitted in the following manner: Relay J1 is energized in the following circuit when the key AT1 is depressed: earth, key ATl, contacts 9e1, and 81'1 in parallel, contact Scl, winding of relay J1, battery, earth. Relay J1 transmits an impulse to the repeater Ue2. Pressing down key ATZ causes relay El to be energized over: earth, key AT2, winding of relay El, resistance Wgi, battery, battery, earth. Relay E1 opens its contact rlel, whereupon relayRl is energized in the following circuit: earth, key ATZ, winding of relay Rl, resistance W9'2, battery, earth. Relay Rl is energized and short circuits relay El by means of its contact 101'1 so that relay El releases with slow action. Relay R1, in addition, opens its contact 81'1 which cuts off the circuit for relayJl during the release period of relay El. This circuit is re-closed after the release of relay El until the switch keys AT1 and AT2 arel released. Relay J l is energized a corresponding period. In order to prevent relay El from being re-energized in the period during which the key AT is depressed and consequently cause a second short impulse to be transmitted, the short circuit for relay Rl is opened at contact 6'fl.V

In the repeater Ue3 the short and the succeeding long impulse received from the signal receiver SE and relay A2 causes the discriminator Dm to be advanced two steps over the same circuit asA that described in connection with the calling operation. The long inipulse causes relay T2 to release which in turn causes relay Y2 to be energized over earth, contacts 1402, 15152, wiper dm2 of the discriminator in position 2, winding I of relay Y2, battery, earth. Relay Y2 closes its cone tacts 2y2 and 3y2 and consequently applies earth to the aand b-leads over the two similar chokes DRl and DR2. Applying earth to the a-lead causes the connecting up, and applying earth to the b-lead is carried out with the object of ob taining a symmetrical load necessary to gain a satisfactory speech transmission from the toll position FP to the subscriber Tn. Relay Y2 is placed in the following locking circuit until the succeeding signal is sent out: earth, contact 16t2, 17g/2, Winding 1l of relay Y2, battery, earth. Relays A2, J2, V2 are released at the end of the long irnpulse. The discriininator advances into its original position. Applying earth to the a-lead now causes the following circuit for relay A3 in the repeater Ue to be formed: earth, choke Drl, contacts 2y2, 28212, winding of relay A3, battery, earth. Relay A3 closes the following circuit for relay V3: earth, contacts 17:13, 15u23, winding of relay V3, battery, earth. Relay V3 is energized and closes a circuit over earth, battery, contacts 9123, 7f3, 7a4, winding ci relay Ye in which circuit relay Yl in the final selector LVM is energized. Relay Y4 is energized and by closing its contacts 3114 and eye causes the still opened speaking leads to be bridged at contacts 6294 and pl. This enables the operator at the toll position FP to communicate with the subscriber Tn by means of her speaking set connected up over the keys ST1 and ST2 so that she can inform him of the incoming toil call. lf the subscri er who is in communication with the subscriber Tn` does not replace his receiver, the operator at the toll position FP is in a position to cut ori the connection.

With 'this object in view she throws over the cut ofi 1lzeys TT?. and TT2 which causes two short and one long impulse to be transmitted. Relay Ji is energized over lrey TTl in the following eircuit: earth, winding or relay J1, battery, earth. Relay J1 is energized and transmits a short impulse over the junction line VL to the voice frequency receiver SE in the repeater Ue2. Dep-ressing the cut ori key causes relay Fl to be energized over earth, key TT2, winding of relay Fl, contact l'gl, battery, earth. By means of contact 15.11 relay Fl cuts oir the above described circuit for relay J 1. The following circuit for relay G1 is then formed: earth, contacts lllcl, 12,71, winding of relay Gl, battery, earth. Relay Gl is energized and closes a fresh circuit for relay J1 as follows: earth, key TTl, contacts 13571, Scl, winding of relay J1, battery, earth. Relay J1 is energized and transmits la second short impulse to the signal receiver SE in the repeater U62. The following circuit for relay Kl is closed in consequence of the energization of relay G1: earth, key TTl, contact 16g1, winding of relay K1, battery, earth. Relay K1 is placed in a locking circuit over its contact 147c1. The energization of relay G1 also cuts of the circuit for slow releasing relay Fl by rneans of oontact l'ir'l. The opening of contact 19c1 prevents relay frorn transmitting an impr-ilse in error to the repeater U82. Relay G1 is released when contact llcl is opened. The release of relay G1 causes relay to be re-energized. Relay F1 now opens its contact lofi permanently. The long impulse is transmitted due to relay D1 being energized on the energization of relay K1 over: earth,

rey TTl, contacts 191761, 15,11, Bcl,

key TTl, contact 20c1,-winding of relay D1, battery, earth. A circuit for relay J 1 is closed over earth, key TTl, contacts ldl, Scl, winding of relay J1, battery, earth when relay D1 is energized. Relay J1 is energized in this circuit until the cut off key TTl is opened and consequently the two relays K1 and D1 are released.

In the repeater U62, the relays J2, T2 and V2 are re-energized over relay A2. Contact 16t2 first breaks the existing locking circuit for winding Il of relay Y2. Relay T2 remains energized during the short The two short and the succeeding long impulses cause the rotary magnet Dm of the discr "nator to be energized and deenergized three tiines. Accordingly, it advances the switch wipers three steps. The switch wiper dini/3 then reaches position 3. The long impulse causes relay T2 to be short circuited over earth, contacts 7a2, 5112. Relay T2 then releases, whereupon relay Z2 can be energized over: earth, ecntacts 14112, 15t2, wiper dm2, contact 3 of the discriminator, winding of relay Z2, battery, earth. Relay Z2 is energized and for the duration of the long impulse applies earth to the a--lead over contacts 2522, 25t2, 2772, 29g2, S5122, and a potential to the b-lead over contacts 24ls2, 2h12, SM2, 3og2, 35112. Y

This causes relays A3 and B3 in the repeater U63 to be energized. Relay A3 is energized in the followinfT circuit: earth, contacts 25a2, 26r'2, 25h72, 29g2, 36222, winding of relay A3, battery, earth. Relay A3 closes its contact l'a which causes ren lay V3 to be energized over earth, contacts 1761.3, 15103, winding of relay V3, battery, earth. Relay B3 was energized over: earth, battery, Contact 2422, 31t2, 3442, 39512, 35112, winding of relay B3, earth.

The relays All and Yll in the final selector LW 4 are now energized, relay AA in the following circuit: earth, contacts 5123, eofi, 6.-3, winding of relay ne, battery, earth, and relay Ye is energized over: earth, battery, contacts 9o3, 7f3, resistance winding of relay Ya, earth. Earth is now applied to the .ii-lead over contacts les, 2cd, 14(24, 1li/ll. If the required subscriber Ta was the calling party in the local call, the preselector of the subscriber Tn will be released over the seized first group selector by earth being applied to the blead with the result that the conversation is now cut off and the nal selector LVM is able to operate. If the subscriber Tn was the called party in the local call, the test relay of the nal selector, seized for the local call, is short circuited by cut off earth being applied direct to the olead over contacts 104, 2cd, 13g/4, 12ml, which releases the c-lead so that the test relay P4 is able to operate as soon as the out off key restored to normal.

The release of the relays in the repeater Uc2 is initiated in the manner repeatedly described above, after the end of the last impulse, by the release of relay A2 which in turn cuts off the circuit for relay J2 and subsequently for relay V2 also. When relays J 2 and V2 have been released, a circuit over which the discriminator is advanced into its original position is formed afresh for the rotary rnagnet Dm of the discriminator as follows: earth, interruptor RU, switch wiper rtm1, contacts 19122, 2052, winding of the rotary magnet Dm, battery, earth. The release of relay C2 and consequently also relay G2 at the end of the conversation is caused by contact 11102 of a not sho-wn relay P2. This relay is energized over the toll position FP while the release is being carried out. The switching operations in connection therewith are of no importance for the invention and therefore have been omitted. The release of relay C2 causes the release of all the succeeding connecting devices.

What is claimed is:

l. In a communicating system, means for transmitting a variable number of short impulses and a succeeding long impulse, and receiving .neans responsive to said long impulse to periorin a switching operation depend-ent upon the number of preceding short impulses,

2. In a communicating system, a transmitter, a receiver, means at the transmitter for transmitting a series or" impulses composed of a variable number or" short impulses succeeded by a long impulse, a plurality of responsive devices at said receiver, means responsive to the transrnitted short impulses for predetermining the one of said responsive devices that corresponds to the number of short impulses received, and means responsive to the succeeding long impulse for actuating the predetermined responsive device.

S. In a telephone system wherein a connection incoming over a trunk line may be further eX- tended by way of a pair of talking conductors, receiving means arranged to respond selectively to a series oi impulses received over said incoming trunk line and comprising a variable number of short impulses followed by a long impulse, and means controlled by said receiving means for applying a combination of potentials to the two talking conductors of the extended connection, the combination of potentials diiering according to the number of short impulses in the received series.

fl. In a switching system, a switch having a contact banlr and a co-operating wiper, means for transmitting a series of impulses to said switch composed ci a variable number of short impulses and a succeeding long impulse, means responsive to said short impulses for positioning the wiper oi said switch onto a contact which depends upon number of short impulses received, and means responsive to the long impulse for closing a circuit including tlie wiper of said switch and the contact on which it is positioned.

5. In a switching system, a receiver responsive to short and long impuls-es, a self-locking relay, means controlled by a long impulse for operating said self-locking relay to close its locking circuit dependent upon the long impulse being preceded by a predetermined number of short impulses, and means responsive to a further received impulse for opening s. id locking circuit to enable said relay to restore.

6. In a iong-distance telephone system, a toll line, automatic switching apparatus at'the distant end of said toll line, means for transmitting impulses of voice-frequency alternating current over said toll line, translating means at the distant end oi said toll line for translating said voice-frequency impulses into suitable impulses for positioning said automatic switching apparatus to extend said toll line, and means at the distant end of said toll line responsive to the transmission or" further impulses oi voicerequency current for performing incidental controlling operations. 7. In a telephone system, a toll line extending to an automatic exchange, means including a toll connector for extending said toll line to subscribers Yzines in said exchange, means for transmitting impulses of alternating current over said toll line to control the setting of said switch, a discriminating switch, means or controlling said switch by additional impulses of alternating current transmitted over said toll line, and circuits controlled by said switch for controlling the operation of said connector in ringing the called party ii idle, offering the call if the called party is busy, and forcing the release of the connection involving the called line.

8. In a telephone system, a toll connector, a line over which setting impulses are transmitted to position said connector on a called line, a discriminating switch associated with said connector, means for variably operating and reoperating said switch a number of times while the connector stands on the called line, and circuits controlled by said switch for initiating various operations in the connector.

FRITZ PIIIJEIDERER.

lli@ 

